Testing machine



Dec. Z2, 1942. Dl C, scoT-r 2,306,111 t TESTING MACHINE Filed Feb'. s,1940 s sheets-sheet 1 INVENTokQ A TTORNEYS.

Dec. 22, 1942. D, Q SCOT-1 2,306,111

' TESTING MACHINE JNVENroR.

BY q" A R EYS.

De.22, 1942. I D, C, SCOTT' 2,306,111

'TESTIG MACHINE Filed Feb. s, 1940 s sheets-sheet s 88 o '1| y//''n -gg90 /94 95 I. l l

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Patented Dec. 22, 1942 TESTING MACHINE David C. Scott, Providence, R.I., assignor to Henry L. Scott Company, a corporation of Rhode IslandApplication February s, 1946, serial No. 317,136v

13 Claims.

This invention relates to a machine for load measurement, moreparticularly vfor exerting known stresses upon a test specimen andmeasuring the resulting strains, and has particular application to theclass of machines frequently referred to as constant load rate testers.

One of the objects ofthis invention is to provide a. machine in whichthe load is applied by means of a weight acting through a lever wherebythe factor entering into the quantity of load applied isthe product ofthe mass and the distance through which the mass `acts about the pivotalpoint or fulcrum of the lever, and to provide for'` one of said factorsbeing constant and the other factor changing the same amount per unit oftime.

Another object of the invention is to maintain the mass factor constantbut to vary the length of the lever or distance of the center of themass from the center of the pivot or fulcrum of the lever at a constantrate per unit of time whereby the change in load rate will be constant.

Another object of the invention is the simplicity of fthe control of theposition of the center of the mass in changing its position to vary thedistance lthrough which it acts about the pivot or fulcrum of the leverfor application of the load onjthe specimen.

With'these and other objects in View, the invention consists of certainnovel features of construction, as will be more fully described andparticularly pointed out in the appended claims.

In the accompanying drawings: Y

Fig. 1 is an elevation of an apparatus designed for applying load inaccordance with my invention;

Fig. 2 is a section on line 2-2 of Fig. 31;

Fig. 3 is a fragmental View showing a modified form of applying load tothe specimen;

application of Vload to a different form of specimen;

Fig. 8 is an elevation of a different form of machine illustrating thedifferent manner of applying load to a specimen either in compression ortension;

Fig. 9 is a sectional view on v substantially line 9-'9 of Fig. 8;

Fig. 10 is a fragmental view of a different form of application of 'loadto the specimeniin'the structre shown in Fig. 8.

Itis desirable in the use of load measurement tofprovide amachinevwhereby' change in the specimen such as elongation thereof willbe taken upV automatically and there will be applied to the specimen aconstant change in load per unit of timeyand in order to provide forthis result I have arranged a lever arm through which a weight'appliesload, the total loadv being the productief the mass or weight and thedistance t the "center of this mass from the pivot or fulcruznof thelever,.the "lever being so' arranged that. ity will swing to take up anyelongation or changrin the specimen as such, which occurs withotaffecting the change in load per unit oftimeg'and thus a constant loadArate is at all tims'fp'rovided for. In a machine of this char-Vactergzfeinasmuch as the load applied equals a product of two factors,one' being the mass of thefweight and theV other the distance `of theweightfrom the fulcrum, I maintain one of these factors constant andvary the other factor at a constant rate so that the product of thefactors willfb'e 4a constant rate, indicating the load japplied to thespecimen; and I have illustrated means for maintaining either the weightfactor constant and the other variable by a controlled rateflan'd wherethe mass is maintained constant,

var'fosmeans for controlling the shifting of the ceriteraof the mass areprovided for. f V

11i? Figs. 1 to 10 inclusive of the drawings, I havefillustrated theweight as constant and have shown various means for controlling theposition ofI this weight along a beam to vary the leverage ofthisconstant mass 'in its application of'load to the specimen.

In Figs. 1 to l0, I have illustrated several means of controlling theposition-of the constant mass with reference to the center 'of the pivotor fulcrum of the beam through which it acts. In Fig. 1, I havepositioned the center of the mass in the same horizontal plane as thecenter of the pivot about which it acts when 'the Lbeam through which itacts is in a horizontal plane. In this way -the function of the mass orweight is always directly proportional to the cosine' of the angle whicha line connecting the center of the pivot and the center of the weightbears to the horizontal; or, in other words, directly pro` portional tothe distance in which the line of the action of gravity through thecenter of the weight is 'from the center of the pivot'of the beamthrough which the weight acts.' In Fig. 5

inasmuch as the center of mass is above or located at one side of ahorizontal plane passing through the center of pivot of the beam whenthe beam is horizontal, a cam for controlling the position of the weighton the beam must necessarily be provided if the constant relationship ofthe point of application of the weight to the beam is to be ,maintainedaccordingto theI cosine law above indicated, and in this showing I haveillustrated the cam surface as provided upon the controller itselfinstead of the weight controller having a vertical straight edge.

by a sprocket chain 35 tr-ained over sprocket gears 36, 36', theseshafts being mounted in suitable bearings 31, 31', 38, 38 at the upperand lower ends of the frames I6, I6'. The shaft 34 is operated atuniform rate of revolutions per minute, such as by a synchronous motor,or through a pulley 39 and through suitable gearing in casing 4U, notillustrated in detail. Thus, the shafts 34, 34' may be operated inunison through threaded sleeves 4I', v4I at the opposite ends of themember 32 for positively `controlling the position of the weight 26 tochange the center of its mass With reference to the drawings in morede-` tail, the base of the various apparatus illustrated is designatedI5; the upright frame is designated I6, I6. A b-eam I1 is pivoted as atI8'upon this frame I6 which is xed to rotate with a drum I9 co-axialwith the pivot of the beam and about which there is trained a flexibleelement 20 secured at 2l to the drum and attached to the clamp 22 .whichengages one end of a specimen 23 held at its opposite end vby means ofaclamp 24 which is supported by a standard25. The beam I1 consists of apair of spaced members which support between. them a weight 25,comprising two cylindrical members mounted upon a shaft 21 and held inspaced relation by a cylindrical member 28.

This weight unit consisting of these several parts 26, 21, and 28 isfree to roll along the upper surface 29 of the beam throughoutsubstantially its length. The center of the mass of the weight 26 willbe the centerof the shaft 21, and when the surface 29 of this beam ishorizontal, the center of the pivot for the beam I8 be the product ofthe mass of the weight 26 and the distance measured alonga horizontalline designated 30 between the center of the pivot I8 and the center ofthe mass or weight 26, and this will be true regardless of theinclination of the beam and the position of the Weight thereon. Forinstance, I have illustrated in dot-dash lines the weight as located ata position where the beam is approximately at an angle of thirty degreesto the horizontal. The line 3| joins the center of the pivot I8 and the-center ofthe sha-ft 21, which is the center of the mass or weight 23.The cosine of this angle will be represented by the line 30 drawnhorizontally through the center of the pivot I8 and graphicallyrepresents the cosine of theangle at unity radius which the line 3Imakes with the horizontal, which is the distance throughwhich the massacts. It thus becomes apparent that if I can move the weight so as toincrease its distance along the horizontal line 30,- from the center I8in uniform increments per unit of time, I will haveaconstant rate ofload increase. Y

I accomplish the above uniformity yby the pro vision of a weightcontroller designated generally 32 .consisting of a member or -crossheadhavi -in the `Same proportion that the m-ember 32 moves to changethedistance along the line 36 of the weight in its action about thepivot III.

This particular manner of applying the test upon the specimen may bevaried, a direct pull in tension being illustrated in Fig. l, whereasbending action is illustrated in Fig. 3 where the specimen'23 is engagedat spaced points by members 42 mounted on standard 25 and at a singlepoint between-these members 42 as at 43 which is attached; bya stirruptothe exible element In Fig.. 5 I haveillustrated a very similar generalarrangementofthe machine and the corresponding parts are similarlydesignated by reference numerals. In this case, however, I haveillustrated a gear segment 45 as also fixed upon the drum I9 which gearsegment engages ya rack 46 guided kas at 41 and 48 from the frame I16and provided with a head 49 to `apply a4 stress in compression upon laspecimen 50 between this head and a fixed .anvil 5I mounted on ,anextension 52 of the framer I6. When a bending test is desired, albracket 53 may be provided from the frame I6 with a specimen 54 mountedbeneath some restraining bar ,55 and clamped as at 56 by set screwV 51to the swinging end ofthe beam which is rocked.

In the showing in Figs. 5, 6 and 1, the beam 60 has the engaging surfaceof 4its runway 6I on a line passing `through the center I8 of the pivotfor the beam so that when lthe beam is in horizontal positionthis-surface will pass through the center I8 and any weightsuchA as 62,supported by thi-s surface will lhave its center of mass above thehorizontal plane of the pivot I3. This beam 60 has spa-ced portionswhich are rabbeted as at 63, while the weight 62v is of cylindrical formand is free to roll along the beam throughout its extent, while theweight is prevented from axial motion by engagement withthe rabbet 63.

Inasmuch as the center 'ofmass 64 of this .weight 62 is above the centerline, it will be necessary to provide -some compensating means to cause`this center to maintain the desired relationship iforrconstant 4loadrate increase, and in order to -provide -for this, the controller 65 isformed with a cam surface 66 which will allow the weight to moveadditional increments along the beam '66. As the elongation of thespecimen takes vplace and the beam tilts, the weight engages the beamatdistances nearer the end thereof, for instance, as illustrated in Fig. 5with the beam at substantiallythirty degrees. In this position theWeight -will beapplied to th-e surface 6I at the point 61-.and notverticallyV below the center 64 as is the case When the weight issupported hin a horizontal position as shown in full lines. Thus, theactual distance throughwhich the weightis applied is the cosine o f theangle made between the line 6I, which represents the surface 'of thebeam contacted, and the lille of the horizontal which would be thepla-neof the vline 6| shown when the beam vis in vfull lines or 'vary thedistance factor, and a 'constant the distance through which the weightacts would be the distance from the center of the pivot to lar surfaceof the controller is represented between the lines 68 and the line 'IIJwhich .must be provided in order that the application of the center ofmass to the beam maintain a relationship proportional to a uniformadvance by the screws 34, 34 which pass through the threaded sleeves 1|,1 of the controller [i5l In Fig. 8 I have illustrated the same generalprinciple as illustrated in Fig. 5 but in this case I have provided thecam surface 'l2 upon the beam 13,while the controller 14 has a Verticalsurface 'l5 for controlling the weight 76 grooved as at 'I1 to t uponand be guided by the beam 13. In this case, the beam is pivoted as at I8and the beam is illustrated in horizontal position while its surfacealong which the Weight moves is inclined on a cam in order to providefor increase in movement of the weight in order that its center of massmay act upon the beam at points which are proportionalto the uniformadvance of the controller 'I5 by meansrof screw 18.

The particular apparatus illustrated in Fig. 8 shows some furthervariations. In this case, the frame 80, 8B supports the beam 'I3 inpivotal relation about the center IS, while a segmental gear 8| isprovided to drive the rack 32 through pinion 83 so as to apply stressupon specimen 84 engaged by clamp 85, which specimen is also engaged atits opposite end by clamp 86 supported Aby sprocket chain 81 trainedover drum 83 and having fixed with this drum an arm 89 movable over asegment 90 and provided with ratchet teeth 9| to be engaged by the pawl92, this arm 89 carrying a suitable Weight 93 to resist the pull on thespecimen, while there is a pointer 94 to indicate the datum line of thecalibrations upon the segment 90 which calibrations are designated 95.

The controller 75 is provided with a cross head 96 slidable on guides91, 91 and advanced uniformly by screw 'i8 through synchronous motor 98,or other suitable means. An anvil 99 is adjustably supported by means ofsei-l screw H10 on the frame 80 so that tests in compression may beutilized for the same mechanism. A bending test may be also provided byattaching a yoke |f0| to the upper end of the rack 82 to engage themiddle of a specimen |02, while a stirrup |63 isl provided for engagingeither side of this middle portion and is attached to the sprocket chain81.

,In Fig. 5, I have illustrated the pointer |28 as fixed to the stand I6,while the calibrated arc |29 is provided upon the drum I9 which moveswith the beam I1.

I claim:

1. In an apparatus of the character described, means for applying a loadto the specimen tested through a rockable beam comprising a beamrockable about a pivot to incline the same with reference to ahorizontal, a weight applied to said beam with its center of mass actingthrough a certain leverage distance from the pivot of said beam, wherebythe turning moment of the beam is equal to the product of two factorsone of which is the said distance and the other of which is the mass ofsaid Weight, and means for moving the weight relative to the beam tospeed motor to operate said'v means.

2. In an apparatus of the character described, means for applying a loadto the specimen tested through a rockable beam comprising a beamrockable about a pivot to incline the same with reference to ahorizontal, a weight applied to said beam with its center of mass actingthrough a certain leverage distance from the pivot of said beam wherebythe turning moment of the beam which is the mass of said weight, andmeans to shift the weight along the beam so regulated as to uniformlychange the effective leverage arm from the center of pivot of the beam.

3. In an apparatus of the character described, means for applying a loadto the specimen tested through a rockable beam comprising ra beamrockable about a pivot to incline the same with 'reference to ahorizontal, a weight applied to said beam with its center of mass actingthrough a certain leverage distance from the pivot ofsaid beam wherebythe turning moment, of the beam is equal to the product of two factorsone of which is the said distance and the other of which is the mass ofsaid Weight, means to position the center of mass in the same horizontalplane With the pivot of the beam when said beam is also in a horizontalposition means to shift the weight along the beam so regulated as touniformly change the effective leverage arm from the center of pivot ofthe beam.

4. In an apparatus ofthe character described, means for applying a loadto the specimen tested through a rockable beam comprising abeam rockableabout a pivot to incline the same with reference to a horizontal, aweight applied to said. beam with its center of mass acting through acertain leverage distance from the pivot of said beam, whereby theturning moment of the beamVV isv equal to the product of two factors oneof which is the said distance and the other of which is the mass of saidweight, a pair of horizontal guides, and a crosshead movable along saidguides and itself provided with a vertical guiding surface to direct theVmovement of said weight relatively along said beam.

5. In an apparatus of the character described, means for applying a loadto the specimen tested through a rockable beam comprising a beamrockable about a pivot to incline the same with reference to ahorizontal, a weight applied to said beam with its center of massacting-through a certain leverage distance from the pivot of said beam,whereby the turning moment of the beam is equal to theproduct of twofactors one of which is the said distance and the other v.of which isthe mass of said Weight, a pair of spaced horizontal guides, and acrosshead movable along said spaced guides and itself provided with avertical slot having a guiding surface to engage and direct the movementof said weight relatively along said beam.

6. In an apparatus of the character described, means for applying a loadto the specimen tested through a rockable beam comprising a beamrockable about a pivot to incline the same with reference to ahorizontal, a weight applied to said beam with its center of mass actingthrough acertain leverage distance from the pivot of said beam, wherebythe turning moment of the beam is equal to the product of two factorsone vof which is the said distance and the other of which is the mass ofsaid weight.. a pair of threaded horizontal guides, and a ,crossheadmovable along said guides by means of threaded engagement therewith anditself provided with a vertical guiding surface to direct the movementof said weight relatively along said beam.

7. In an apparatus of the character described, means for applying a loadtothe specimen tested through a rockable beam comprising a beam rockableabout a pivot to incline the same with referenceto a horizontal, aweight applied to said beam.with its center of mass acting through acertain leverage distance from the pivot of said beam, whereby theturning vmoment of the beam is equal to the -product of two factors oneof which is the said distance and the other of which is the mass ofsaid-weight, a pair of threaded horizontal guides, and a crossheadmovable along said guides by means of threaded engagement therewith anditself provided with a vertical slot perpendicular to Vsaid guidesv todirect the movement of said. weight. 1

8. In an apparatus `of the character described, means for applying aload to the specimen tested through a rockable beamy Ycomprising a beamrockable about a pivot to incline the same with reference to ahorizontal, a weight having rolling engagement with said beam `with itscenter. of massacting through a certain leverage distance from the pivotof saidbeam,V whereby the turning moment of the beam is equalto theproduct of two factors one of which is the said distance and the otherof which isthe mass of said weight, a pair of horizontal guides, and acrosshead movable along vsaid guides to vary its position from the pivotof said beam, said crosshead engaging said weight to control itsmovement along said beam. Y f v 9. In an apparatus of the characterdescribed,

means for applying a load to the specimen tested through a rockable beamcomprising a beam rockable about a pivot to incline the same withreference to a horizontal, a weight having rolling engagement with saidbeam with its center of mass acting through a certain leverage distancefrom the pivot of said-beam, whereby the turning moment of the beam isequal to the product of two factors one of which is the said distanceand the other of which is the mass of said weight, a pair of horizontalguides, a crosshead movable along said guides to vary its position fromthe pivot of said beam, said crosshead engaging said weight to controlits movement along said beam, and means to move said crosshead touniformly vary the effective leverage distance of the application of theweight to the beam.

10. In an apparatus of the vcharacter described, means for applying aload-tothe specimen tested through a rockable beam comprising a beamrockable about a pivot to incline the same with reference to ahorizontal, a weight having rolling engagement with said beam with itscenter of mass acting through a certain leverage distance Afrom thepivot of said beam, whereby the turning `moment of the vbeam is equal tothe product of two factors one of which isthe said distance and ,theother .of which is the mass of said weight,

a pair of horizontal threaded guides, a crosshead .movable along saidguides by means yof threadedengagement ,therewith to vary its positionfrom .the pivot of said beam, said crosshead having a slot'into which aportion of the weight extends to control the rolling movement Aof theweight along said beam, and means to uniformly turn both threaded guidesin'unis'on to vary the eifective leverage distance of the application ofthe weight to the beam.

11. In an apparatus of the character described, means for applying aload to the specimen tested through a rockable beam comprising a beamrockable about a pivot to incline the same with reference to ahorizontal, a weight applied to said beam with its center of mass actingthrough a certain leverage distance from the pivot of said beam wherebythe lturning moment of the beam is equal to the product of two factorsone of which is the said distance and the other of which -is the mass ofsaid weight, cam surfaces engaging said weight to shift the weight alongthe beam at a constant rate of change from the center of the pivot ofthebeam.

1 2. In an apparatus of the character described, means for applying aload to the specimen tested through a rockable beam comprising a beamrockableabouta pivot to incline the same with reference to a horizontal,a weight applied to said beam with its center of mass acting through acertain leverage distance from the pivot of said beam whereby theturning moment of the beam is equal to the product of two factors one ofwhich is the said distance and the other of which is the mass of saidweight, a controller for said weight having a cam surface engaging saidweight to permit movement of the weight as the beam tilts and maintainthe point of application of force to the beam at a uniformly changingdistance from the center of the pivot of the beam.

13. In an apparatus of the character described, means for applying aload to the specimen tested through a rockable beam comprising a beamrockable about a pivot to incline the same with reference to ahorizontal, a Weight applied to said beam with its center of mass actingthrough a certain leverage distance from the pivot of said beam wherebythe turning moment of the beam is equal to the product of two factorsone of which is the said distance and the other of which is the mass ofsaid weight, a weight controller, said beam being provided with a camsurface to control movement of the weight to maintain the point ofapplication ofv force to the beamat a uniformly changing distance fromthe center of the pivot of the beam as the beam tilts.

DAVID C. SCOTT.

